He has been arguing in a circle; there is thus a see-saw between the hypothesis and the fact.

Wherefore let him that thinketh he standeth take heed lest he fall.

• Jack, could you take a look at my computer? It won't boot up.
• I'm on it!

The cab stopped, and out jumped a man in a coarse Petersham great coat, whitey-brown neckerchief, faded black suit, gambooge-coloured top-boots, and one of those large crowned hats, formerly seldom met with, but now very generally patronised by gentlemen and costermongers.